Floral biology, pollination requirements and behavior of floral visitors in two species of pitaya

Breno Magalhães Freitas,Isac Gabriel Abrahão Bomfim,Márcio Cleber De Medeiros Corrêa,João Paulo De Oliveira Muniz

doi:10.5935/1806-6690.20190076

Breno Magalhães Freitas, Isac Gabriel Abrahão Bomfim + Show 2 more

Open Access

https://doi.org/10.5935/1806-6690.20190076

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Abstract

The present work aimed to study floral biology, pollination requirements and the behavior of floral visitors in two species of pitaya, Hylocereus undatus and H. polyrhizus, in Northeastern Brazil. The experiment was carried out through diurnal and nocturnal observations and the use of flowers bagged or accessible to visitors. Results showed that flowers of both species are similar both in anatomical and functional traits. They are large, with nocturnal anthesis onset and attract night and daytime flower visitors. The floral visitors found were sphinx moths, ants, wasps and bees, with Apis mellifera accounting for 86.1% of visits to flowers. The H. undatus species is independent of biotic pollination to set and produce large and well-shaped fruits, but H. polyrhizus shows limited self-pollination and requires biotic pollination to set fruits and also to produce larger fruits. In this case, A. mellifera appears as the most likely pollinator. It is concluded that biotic pollination deficit is a limiting factor for the productivity of H. polyrhizus , but not to H. undatus under the conditions studied and that the role of pollinators, especially A. mellifera , in the quality of the fruits produced by both pitaya species needs to be investigated.

Highlights

The pitaya (Hylocereus spp.) is a new and promising fruit in the market, and is produced by several related species belonging to the family Cactaceae
Because all pitayas are cacti species, several publications point out bats as the natural pollinators of their flowers (LE BELLEC, 2004; WEISS; NERD; MIZRAHI, 1994)
Other studies present bats as the most efficient nocturnal pollinators (VALIENTBANUET et al, 2007; WEISS; NERD; MIZRAHI, 1994) while bees play this role during daytime pollination, even having a much shorter period of time to visit the flowers (LE BELLEC, 2004; MARQUES et al, 2011a;)

Summary

Introduction

The pitaya (Hylocereus spp.) is a new and promising fruit in the market, and is produced by several related species belonging to the family Cactaceae. Among the many species of pitayas, four stand out in global cultivation and distribution: H. undatus, H. polyrhizus, H. costaricensis and Selenicereus megalanthus (ORTIZHERNÁNDEZ; SALAZAR, 2012). Because it is a new crop, there is little literature on floral biology and pitaya pollination requirements, which may limit its productivity. Because all pitayas are cacti species, several publications point out bats as the natural pollinators of their flowers (LE BELLEC, 2004; WEISS; NERD; MIZRAHI, 1994). A study by Valiente-Banuet et al (2007) carried out in Mexico, where the plant occurs naturally, did not find nectar in the flowers of Hylocereus undatus, suggesting that bats probably visit flowers of this species in search of pollen. Bees definitely visit pitaya flowers only for pollen (LE BELLEC, 2004)

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